The pathogenic processes by which microorganisms elicit their adverse effects on subjects are generally complex and require a defined sequence of events that implicate multiple microbial components. If left unchecked, the proliferation of organisms can impair the subject, resulting in chronic infection, or even death. It is frequently necessary to bolster host defense mechanisms with exogenous factors such as antibiotics to aid clearance of the infecting organism from the subject.
Over time, and due in part to injudicious use of existing antibiotic treatment regimens, organisms are becoming increasingly resistant to the various exogenous factors available. For example, resistance of bacteria to fluoroquinolones and beta-lactams has been reported and will most probably increase over the next decade. Fluoroquinolone resistance isolates from around of the world in community-acquired pneumonia have also been increasingly described. Further, there is a serious decrease in susceptibility of E. coli strains to the beta-lactams (e.g., amoxicillin), due to the presence of R-TEM enzymes, to cotrimoxazole and trimethoprim. These reports exemplify the necessity and continued need for the discovery and development of new antimicrobial therapeutics in order to provide alternative and more powerful treatment regimens against increasingly resistant microorganisms.